Severe Thunderstorm Watch Now Issued For Connecticut: Here's What To Know

UPDATE: The National Weather Service has issued a severe thunderstorm watch for the entire state of Connecticut except New London County up until 9 p.m.

The threat of severe thunderstorms is increasing across Connecticut on Thursday.

"In advance of a cold front, strong to severe storms will be possible from mid-afternoon into the early evening hours. Lightning, heavy rain, damaging wind gusts, and hail will be the top threats. Within the region, an isolated tornado can’t be ruled out," said WFSB 3 TV meteorologists.

The National Weather Service said between 4 and 10 p.m. Thursday is the best chance for severe weather, which may include "damaging winds and heavy downpours, but large hail and an isolated tornado also cannot be ruled out."

The sun is forecast to appear in the afternoon hours, which will drive temperatures inland into the 90s.

"Those temps will feel even hotter with near oppressive levels of humidity: heat index values likely reach between 95 and 100 inland! A Heat Advisory and an Air Quality Alert have been issued for parts of the state --- those in sensitive groups should plan to spend time inside and near A/C," said WFSB 3 TV meteorologists.

Weekend forecast details

"Saturday looks great. Under ample sunshine, temps peak in the mid to upper 80s with a slight uptick in humidity. We’ll be monitoring a cluster of storms that will be passing through the region at night," said WFSB 3 TV meteorologists. "There is a chance we could escape them… but if they were to clip CT, they’d move through early Sunday. Thereafter, Sunday is warmer and muggier compared to Saturday. Temperatures inland top out near 90, and in the mid-80s along the shoreline."

Heat wave really takes off

"For those wanting multiple days of summer heat… you’re in luck! In fact, we’re forecasting the hottest weather of the year, and since last June. We’ve declared *First Alert Weather Days* Monday through Wednesday, for a dangerous combination of heat and humidity. Daily high temperatures will challenge records for June 23rd, 24th, and 25th (for Hartford and Bridgeport), there’s even a chance that on Tuesday the high could hit 100 (Hartford). This is notable because 100 is the record high for the month of June!..Furthermore, with oppressive levels of humidity, heat index values will surpass the century mark!" said WFSB 3 TV meteorologists. (Read more at WFSB 3 TV).

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Connecticut’s extreme hot weather protocol activated for the first time in 2025

Gov. Ned Lamont announced that due to a weather forecast indicating that Connecticut will experience a multi-day stretch of exceptionally hot and humid conditions, he is directing Connecticut’s Extreme Hot Weather Protocol to be activated effective at 12 p.m. on Sunday, June 22, 2025, and remaining in effect through at least 8 p.m. on Wednesday, June 25, 2025.

This is the first time this year that the protocol is being activated. The current forecast is showing that temperatures will exceed more than 90 degrees over this period, with a heat index that could range from between 100 to 105 degrees.

The purpose of activating the protocol is to ensure that the most vulnerable populations receive protection from the hot conditions. While enacted, a system is set up for state agencies, municipalities, and other partners to coordinate with United Way 2-1-1 to make sure that information regarding cooling centers is available statewide, providing a location for those in need of relief.

Cooling centers will be available throughout the state. Anyone in need of a place to get out of the heat can locate their nearest cooling center by calling 2-1-1 or viewing the list that will be published online at 211ct.org.

The following actions are implemented while Connecticut’s Extreme Hot Weather Protocol is enacted:

• The Connecticut Department of Emergency Services and Public Protection’s Division of Emergency Management and Homeland Security uses its WebEOC communications network, which is an internet-based system that enables local, regional, and state emergency management officials and first responders to share up-to-date information about a variety of situations and conditions.
• Municipalities and other partners submit information on the opening of cooling centers into the WebEOC, providing a real-time database on the availability of these locations statewide. United Way 2-1-1 uses the system to act as a clearinghouse to assist residents in locating a cooling center.
• Regional coordinators from the Division of Emergency Management and Homeland Security monitor WebEOC to respond to any requests from municipalities for state assistance.
• The energy utility companies provide the state with regular updates regarding the impact of the weather conditions on their respective utilities throughout the duration of the protocol.

Here are the forecast details for southern Connecticut via the National Weather Service:

Juneteenth: A chance of thunderstorms after 5pm. Partly sunny, with a high near 88. Light south wind increasing to 6 to 11 mph in the morning. Chance of precipitation is 30%.

Tonight: A 30 percent chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 66. Southwest wind 6 to 13 mph.

Friday: Sunny, with a high near 83. West wind 9 to 11 mph.

Saturday: Mostly sunny, with a high near 86. Southwest wind 3 to 8 mph.

Sunday: Partly sunny, with a high near 86.

Monday: Mostly sunny, with a high near 89.

Tuesday: Sunny, with a high near 93.

Wednesday: Sunny, with a high near 90.

Here are the forecast details for northern Connecticut via the National Weather Service:

Juneteenth: Scattered showers and thunderstorms, then showers likely and possibly a thunderstorm after 5pm. Areas of fog before 9am. Otherwise, cloudy, then gradually becoming mostly sunny and hot, with a high near 93. Heat index values as high as 100. Light south wind becoming southwest 8 to 13 mph in the morning. Winds could gust as high as 24 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Tonight: Showers and thunderstorms likely before 9pm, then scattered showers between 9pm and 11pm. Mostly cloudy, with a low around 64. South wind 9 to 11 mph, with gusts as high as 21 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Friday: Mostly sunny, with a high near 83. West wind 10 to 14 mph, with gusts as high as 32 mph.

Saturday: Mostly sunny, with a high near 87. Calm wind becoming west 5 to 7 mph in the afternoon.

Saturday Night: A chance of showers and thunderstorms, mainly after midnight. Mostly cloudy, with a low around 68. South wind around 6 mph. Chance of precipitation is 30%.

Sunday: A chance of showers before 9am. Partly sunny, with a high near 88. West wind 6 to 10 mph. Chance of precipitation is 30%.

Monday: Mostly sunny and hot, with a high near 95. Southwest wind 3 to 7 mph.

Tuesday: Sunny and hot, with a high near 98. Calm wind becoming west 5 to 8 mph in the morning.

Wednesday: Mostly sunny and hot, with a high near 94. North wind 5 to 7 mph becoming west in the afternoon.